In general, computing devices have been used to provide user interaction with printed material (e.g., a book, a photograph, etc.). User interaction using a computing device has become popular as a learning tool. For example, a child may use a computing device in order to select an object in a book and in response to the selection a representation of the object is read out by the computing device. A computing device may be equipped with additional features. For example, the computing device may further provide spelling for the selected object and use the selected object in a sentence.
Interaction between a computing device and printed material (e.g., a book) may be implemented through encoding the printed material with a plurality of codes. The code may be a plurality of unique dot patterns. In general, dot patterns are used in order to determine the relative location of a printed or written element on the printed material such that the element can be identified. Registration of the element is accomplished via the elements relative to the unique dot pattern.
Facilitating user interaction described above requires the printed material (e.g., a book) to be encoded with dot patterns. Therefore, by detecting the dot patterns, printed elements on a printed material can be detected and determined by using a computing device. Encoding printed material is a costly process because complex printing technology is required for the printed material and dot patterns to exist together.
Moreover, costly printing technology does not solve the problem for printed materials that are already in circulation but lack dot patterns for detection by a computing device. Therefore, for these publications there is no way for a pen based computing device to detect printed elements.
Also, the dot pattern used to provide position is unique and limited in area. Large numbers of publications, e.g., periodic publications, can threaten to utilize the pattern space to exhaustion. Conservation of the dot area would be useful.